"Humane Vitae came as a surprise to many Vatican observers. Though an encyclical issued in 1930 already prohibited birth control, a papal commission had been assembled to revisit that ban, and a majority of the commission members suggested that it be dropped. Moreover, a Vatican II document stipulated the right of man "to follow his conscience." Indeed, Catholics were already using contraception. The birth control pill had been legalized by a Supreme Court decision, and a 1965 survey of Catholic women found that more than half were using some forbidden contraceptive method. By 1973, that proportion had grown, with two of three [married]] Catholic women reported to be relying on birth control to avoid pregnancy. The Humanae Vitae encyclical apparently had had little effect."